Publisher Summary The Golgi region is a main cellular crossroads where biosynthetic and endocytic pathways meet and molecules are targeted to their further and final destinations. The region's organization and architecture are highly dynamic and change with altered functional conditions. The Golgi apparatus constitutes a continuous membrane system that is composed of subunits: stacks of flat cisternae associated with multiple vesicles and interconnected by acomplex saccular–tubular system. Transitional elements of the endoplasmic reticulum (ER), transport vesicles, and the cis and trans Golgi reticulum are in close spatial relationship to the Golgi stacks. The individual stacks of cisternae are composed of several functionally different subcompartments. This chapter discusses the studies performed to morphologically distinguish among functional subcompartments of the Golgi apparatus. It focuses on an ectinocytochcmical exploration of the Golgi region in various cell types. This technique makes use of the sugarbinding capacity of lectins. On the basis of interactions of lectins with glycoconjugates present in the Golgi membranes and lumina, subcompartments of the Golgi apparatus can be distinguished. These morphologically demonstrable subsections are related to functional subcompartments and may reflect modifications occurring at the sugar chains of glycoconjugates traversing the Golgi stacks on the way to their further and/or final destinations.